Semiconductor memory devices include, for example, static random access memory, or SRAM, and dynamic random access memory, or DRAM. DRAM memory cell has only one transistor and one capacitor, so it provides a high degree of integration. DRAM requires constant refreshing. Also, its power consumption and slow speed limit its use mainly for computer main memories. An SRAM cell, on the other hand, is bi-stable, meaning it can maintain its state indefinitely as long as an adequate power is supplied. SRAM can operate at a higher speed and lower power dissipation, so computer cache memories use exclusively SRAMs. Other applications include embedded memories and networking equipment memories. There are several types of SRAM cells, e.g., 6-transistor (6T) SRAM, dual-port 8-transistor (8T) SRAM, etc.